Vocabulary is an area that requires foreign language learners to work independently and continuously both in and out of class. In the Japanese EFL setting, for example, more than 97% of the population experiences approximately six years of English education at secondary school during which time they are required to learn approximately 3,000 words (i.e., lemmas). Given the lexical distance between Japanese and English, this leaves Japanese university EFL learners with a long way to go before they can acquire a sufficient number of words to comprehend authentic texts in English. To help Japanese university EFL learners sustain their vocabulary learning, the researchers have developed "Lexinote," an e-portfolio system that allows learners to record and save the target words they encounter online, to search for them in online dictionaries, to practice them in several ways including written and oral rehearsals according to word familiarity (i.e., level of understanding of each lexical item), and to share their own output with peers. Learners are guided to monitor and control their vocabulary learning metacognitively according to word familiarity. "Lexinote" also provides learners with multimedia materials such as audio lessons for business and academic vocabulary development and online video lectures to prepare for classes conducted in English. Instructors can monitor students' learning records by number of words recorded, by type of practices chosen, and by how frequently they edit their learning records. This paper introduces the key concepts and basic functions of "Lexinote" and discusses how it can benefit learners, instructors, CALL researchers and developers with results from a survey on learners' perceptions.